My thoughts are:
(1) Secure your place, autos, and persons first with alarms, sensors, dog, gun, etc. I’d feel comfy with a Remington 870 and learn how to use it if you don’t. Hopefully you are in a split level condo with the bedrooms upstairs. If so, make sure there aren’t any ways for others to climb up into the 2nd floor windows. If there’s ever an illegal entry, you can grab the shotgun and guard the staircase. Be sure that your pumping (loading) of the round is well heard. Have your partner call 911 while you wait.

(2) Actually try to be friendly with the malefactors. Wave hi/bye, introduce yourself, make idle chit-chat. They aren’t going to be in your inner-most circle of friends, but this can help to make things a bit more comfortable and will help your standing after step 3…

(3) Pursue all legal and non-violent means at your disposal to remedy the situation. Some tips have been mentioned previously. When the legal stuff starts to come down, the malefactors will start to make a list of the neighbors who might have done it. They’d be much more inclined to think it’s one of the other neighbors, not you.